UNIVERSITY    OF    CALIFORNIA 
COLLEGE     OF     AGRICULTURE  _ 

AGRICULTURAL    EXPERIMENT    STATION 
BERKELEY,    CALIFORNIA 

CIRCULAR  288 
May,  1925 

PHYLLOXERA  RESISTANT  VINEYARDS 

BY 

L.  O.  BONNET 


Nursery  of  bench  grafts. 


INTRODUCTION 

The  Phylloxera  is  the  most  widespread  and  destructive  insect  which 
attacks  the  vine.  It  exists  in  all  the  principal  grape  growing  regions  of 
the  world,  and  in  most  of  them  has  destroyed  all  or  the  greater  part  of 
the  vines  which  grew  there  before  its  arrival. 

In  California,  it  has  found  its  way  into  all  the  large  grape  growing 
districts  and  has  destroyed  most  of  the  original  vineyards  in  the  north- 
central  coast  counties.  According  to  the  State  Department  of  Agri- 
culture, the  following  counties  are  free  from  Phylloxera : 


Alpine 

Mariposa 

San  Bernardino 

Amador 

Merced 

Santa  Barbara 

Del  Norte 

Modoc 

Shasta 

Humboldt 

Mono 

Sierra 

Imperial 

Nevada 

Siskiyou 

Inyo 

Orange 

Stanislaus 

Kern 

Plumas 

Tehama 

Lake 

Eiverside 

Trinity 

Lassen 

San  Benito 

Ventura 

Los  Angeles 

Z  UNIVERSITY    OF    CALIFORNIA — EXPERIMENT   STATION 

The  Insect. — The  insect  is  a  native  of  the  eastern  United  States, 
particularly  of  the  Mississippi  Valley,  where  it  lives  upon  the  native 
species  of  Vitis  (''grape  vines").  In  its  native  home,  it  has  several 
forms  or  stages.  One,  the  gall  form,  lives  on  the  leaves  throughout  the 
summer.  Some  of  the  gall  insects  migrate  to  the  root  where  they  live 
and  multiply  for  an  indefinite  time.  Some  of  these  root  insects, 
usually  in  late  summer,  produce  a  winged  form  which  emerges  from 
the  ground  and  by  flying,  with  the  help  of  the  wind,  carries  the  pest 
into  new  vineyards.  The  winged  form  lays  eggs  upon  the  leaves  of 
the  vines  it  reaches  and  these  eggs  hatch  into  the  fourth  or  sexual  form. 
The  female  insect  produced  in  this  way  lays  the  winter  egg  under  the 
dry  bark  which  protects  it  during  the  winter.  In  the  spring  when 
the  leaves  of  the  vine  are  formed,  the  winter  egg  hatches  and  the  insect, 
finding  its  way  to  a  leaf,  gives  rise  to  a  new  generation  of  gall  insects. 

In  California,  only  the  root  form  occurs  in  most  cases.  The  winged 
form  appears  occasionally  in  large  numbers  in  a  few  districts  but  there 
seems  reason  to  believe  that  it  does  not  lay  eggs  or  produce  the  sexual 
form.    The  gall  form  has  never  been  found  in  California. 

The  insect  is  related  to  the  aphids  or  plant  lice  and,  in  all  forms, 
is  extremely  small — just  visible  to  the  unaided  eye — but  large  enough 
to  be  seen  readily  with  an  ordinary  hand  magnifying  glass. 

Injury  to  the  Vine. — The  only  serious  injury  done  to  the  vine  is 
due  to  the  work  of  the  root  insect,  which  punctures  the  roots,  forming 
''nodosities"  at  the  tips  of  the  rootlets  and  "tuberosities"  on  the  large 
roots.  The  tip  galls  stop  the  growth  of  the  rootlets,  and  the  decay 
of  the  swellings  on  the  large  roots  destroys  the  bark  and  growing  layers 
and  finally  causes  the  death  of  the  whole  root  system. 

Degrees  of  Susceptihility. — Some  species  of  vines  are  readily 
attacked  by  the  insect  and  others  are  almost  immune. 

The  European  species,  Vitis  vinifera,  of  which  our  Californian 
grapes  are  varieties,  is  the  most  susceptible  of  all.  The  American 
species,  of  which  there  are  nearly  twenty,  possess  resistance  of  varying 
degrees,  from  practically  complete  immunity  to  a  susceptibility  little 
less  than  that  of  V.  vinifera. 

The  degree  of  resistance  of  a  vine  is  expressed  by  numbers  from 
0,  representing  the  maximum  susceptibility  of  Vinifera,  to  20,  repre- 
senting immunity  or  the  theoretical  maximum  resistance  of  a  vine 
which  the  Phylloxera  cannot  attack  at  all.  The  following  list  gives 
the  relative  resistance  of  the  principal  species  which  interest  the  grape 
grower : 


ClKC.  288]  PHYLLOXERA  RESISTANT   VINEYARDS 

Phylloxera  Eesistance  of  Species  of  Vitis 


Species — 

Origin 

Resistance 

1.  V.  rotundifolia 

American 

19 

2.  v.  vulpina  (riparia) 

American 

18 

3.  v.  rupestris 

American 

18 

4.  V.  cordifolia 

American 

18 

5.  V.  berlandieri 

American 

17 

6.  V.  aestivalis 

American 

16 

7.  V.  lincecumii 

American 

14 

8.  V.  labrusca 

American 

3-5 

9.  V.  californica 

American 

4 

10.  V.  vinifera 

European 

0-1 

All  the  American  species  have  a  high  degree  of  resistance  with  the 
exception  of  Labrusca  and  Californica  which  are  but  little  better  than 
Vinifera  in  this  respect.  Hybrids  of  these  species  have  degrees  of 
resistance  intermediate  between  those  of  the  parents. 

Means  of  Defense. — The  means  of  defense  against  the  Phylloxera 
are: 

Prevention. — Quarantine  against  infested  material  and  disinfec- 
tion of  planting  stock.  This  is  very  useful  in  delaying  the  spread  of 
the  insect,  sometimes  for  many  years,  but  it  is  seldom  that  it  can  be 
relied  upon  for  permanent  protection.* 

Cure. — There  is  no  certain  cure  if  the  insect  has  obtained  a  foot- 
hold in  the  vineyard.  Temporary  relief  can  be  obtained  by  **  sub- 
mersion," that  is  by  keeping  the  vineyard  covered  with  water  to  a 
depth  of  several  inches  continuously  for  from  three  to  five  weeks  dur- 
ing the  dormant  season.  It  is  very  rare  that  this  is  practicable  and, 
in  any  case,  the  insects  are  seldom  all  destroyed,  and  the  flooding  must 
be  repeated  every  few  years. 

The  number  of  insects  can  also  be  reduced  below  the  danger  point 
by  treating  the  soil  with  carbon  bisulfid,  but  this  is  expensive  and 
must  also  be  repeated  periodically.  Applying  paradichloro-benzine 
promises  to  be  effective,  but  has  not  been  thoroughly  tested  and  is, 
moreover,  also  very  expensive.  In  most  cases  there  is  no  practical 
cure  known  for  a  vineyard  infested  with  Phylloxera. 

Immimity. — There  are  two  methods  of  permanent  protection ;  one 
of  general  applicability,  and  one  possible  under  special  conditions. 

The  latter  is  based  on  the  fact  that  vines  of  any  kind  are  immune 
from  attack  if  growing  in  extremely  sandy  soil,  similar  to  the  ''blow 
sands''  of  some  of  our  grape  growing  districts.  A  soil,  to  be  com- 
pletely immune,  must  contain  at  least  60  per  cent  of  silica  sand. 

*  See  Circular  226,  '* Protection  of  Vines  from  Phylloxera,**  which  can  be 
obtained  by  applying  to  the  College  of  Agriculture,  Berkeley,  California. 


4  UNIVERSITY    OF    CALIFORNIA EXPERIMENT   STATION 

Smaller  amounts  afford  temporary  or  partial  protection,  probably  by 
interfering  with  the  movements  and  spread  of  the  insect. 

The  only  method  of  general  applicability  is  the  use  of  resistant 
vines.  These  can  be  used  in  two  ways :  (a)  as  direct  bearers.  This 
means  the  growing  of  vines  of  resistant  varieties  for  fruit.  Unfor- 
tunately, quality  of  fruit  and  resistance  to  Phylloxera  are  inversely 
proportional — the  more  resistant  the  variety,  the  poorer  the  fruit,  the 
better  the  fruit  of  the  variety,  the  lower  the  resistance.  (&)  As 
grafting  stock.  If  we  use  a  resistant  vine  as  a  root  stock  and  graft 
on  it  a  variety  which  produces  the  kind  of  fruit  we  require,  we  have  a 
compound  vine  whose  roots  are  safe  from  Phylloxera  and  whose  crop 
is  of  the  quality  desired.  The  root  has  no  unfavorable  influence  on 
the  quality  of  the  fruit  and  the  top  does  not  diminish  the  specific 
resistance  of  the  root. 

The  use  of  resistant  root  stocks,  therefore,  is  the  method  used  almost 
exclusively  in  most  of  the  vineyard  districts  of  the  world  as  the  means 
of  protecting  vineyards  from  Phylloxera.  This  circular  is  concerned 
with  the  practical  application  of  this  method  for  vineyards  in 
California. 

EESISTANT  EOOT  STOCKS 

The  selection  of  the  stock  is  one  of  the  most  important  parts  of  the 
problem,  because  on  it  depends  the  productiveness  and  the  duration  of 
the  vineyard.  When  a  stock  has  been  well  selected,  that  is  to  say,  when 
it  is  adapted  to  the  soil  and  climate,  and  also  suited  to  the  scion  desired, 
success  will  follow  if  proper  cultural  methods  are  used,  while  a  poor  or 
bad  selection  will  inevitably  result  in  a  partial  or  total  failure. 

Varieties  Suitable  for  California. — Resistant  stocks  are  classified 
into  three  groups :  American  stocks,  i.e.,  varieties  of  a  pure  American 
species;  American  x  American  stocks,  i.e.,  crosses  between  two  or  more 
American  species ;  and  Vinif  era  x  American  stocks,  i.e.,  crosses  between 
Vinifera  and  American  species.  Each  of  these  groups  contains  many 
varieties,  but  some  have  been  rejected  for  various  reasons,  after  trial 
and  experience,  so  that  today,  the  problem  of  what  stock  to  plant  does 
not  present  the  pitfalls  it  did  some  years  ago.  Experience  in  this 
matter  is  meager  in  California,  however,  even  for  the  coast  counties 
where  more  or  less  successful  resistant  vineyards  have  been  established 
for  twenty  years,  and  new  problems  arise  with  the  spread  of  the  pest 
into  vineyards  growing  under  different  soils  and  climatic  conditions. 

After  the  experience  of  the  past,  here,  and  in  other  grape  growing 
countries,  few  stocks  are  being  used  of  the  thousands  that  have  been 
produced  and  tried.    The  following  table  gives  the  standard  varieties 


CiRC.  288]  PHYLLOXERA    RESISTANT    VINEYARDS  5 

which  have  been  found  successful  in  California  and  also  a  few  others 
which,  though  new,  are  very  promising  on  account  of  the  results  they 
have  given  in  France  and  Algeria  under  conditions  similar  to  those 

of  California. 

List  of  Resistant  Stocks 

American —  Riparia  x  Rupestris  101-14 

Riparia  Gloire  Riparia  x  Berlandieri  420A 

Rupestris  St.  George  *Berlandieri  x  Novo  Mexicana  31R 

American  x  American —  *Rupestris  x  Berlandieri  57R,  90  R,  llOR 

Riparia  x  Rupestris  3309  Vinifera  x  American  1616,  1613 

Riparia  x  Rupestris  3306  Chasselas  x  Berlandieri  41B 

The  stocks  contained  in  the  above  table  are  not  suited  to  all  soils 
nor  to  all  climates ;  in  fact,  the  diversity  of  their  original  habitats  and 
their  characteristics  are  an  indication  of  differences  in  adaptation. 
The  following  notes  on  these  stocks  are  based  on  experiments  carried 
out  in  California,  on  the  works  of  Professor  L.  Ravaz,  on  an  article 
entitled,  ''Les  Meilleurs  Porte-Greff'es  actuels, "  by  A.  Bonnet  and  on 
published  accounts  of  results  obtained  in  other  countries  especially  in 
Algeria.  They  should  be  consulted  for  the  selection  of  the  best  stock 
for  a  given  soil  and  climate. 

Riparia  Gloire. — This  is  a  stock  for  the  rich,  loose,  moist  bottom 
soils  of  the  coast  region,  especially  of  the  fog  belt.  This  variety  of 
Riparia  ripens  the  fruit  of  its  scions  early  and  favors  the  production 
of  large  berries  and  well  set  bunches.  •  It  roots  and  grafts  easily.  It  is 
entirely  unsuited  to  the  interior  regions  of  California  and  its  use  in  the 
state  is  in  consequence  very  limited. 

Rupestris  St.  George  (Syn.  R.  du  Lot). — This  is  the  most  interest- 
ing variety  of  its  species  and  is  grown  more  in  California  than  any 
other  stock.  It  grows  with  great  vigor  in  deep  soils,  as  long  as  the 
soils  are  not  too  compact  or  dry.  Deep  soil  is  necessary  for  its  plung- 
ing root  system.  In  shallow  soils,  dry  or  wet,  it  always  fails.  It  thrives 
in  the  hot  climate  of  the  interior  valleys.  Rupestris  St.  George  roots 
and  grafts  well,  and,  for  these  seasons,  has  been  propagated  in  Cali- 
fornia almost  to  the  exclusion  of  other  stocks.  But,  its  indiscriminate 
use  has  led  in  some  soils  and  under  certain  climatic  conditions  to 
failures.  This  stock  does  not  favor  good  setting  of  blossoms  and,  for 
this  reason,  should  not  be  grafted  with  varieties  subject  to  ''Shelling," 
' '  Shot  berries  "  or  ' '  Coulure. ' '  In  other  words,  it  tends  to  diminish  the 
productiveness  of  the  scion.  This  tendency  is  less  with  some  varieties 
and  diminishes  with  age.  It  withstands  white  alkali  to  a  certain 
degree. 

*  The  varieties  marked  with  an  asterisk  are  new  hybrids  and  included  simply 
as  worthy  of  trial. 


b  UNIVERSITY    OF    CALIFORNIA EXPERIMENT    STATION 

Riparia  x  Bupestris  3309. — A  stock  having  the  general  adaptation 
of  its  parents.  It  utilizes  soils  of  medium  fertility  better  than  Riparia 
Gloire  and  also  those  which  contain  more  limestone  than  this  stock  can 
withstand.  3309  does  not  force  vegetative  growth  so  much  as  Rupestris 
St.  George  and  promotes  better  setting  of  fruit.  It  has  been  used 
indifferently  with  3306,  but  experience  has  shown  3309  the  better 
suited  to  light,  gravelly  and  loose  soils.  It  roots  and  grafts  well.  These 
valuable  characteristics  explain  the  large  use  which  has  been  made 
of  this  stock.  It  appears  to  be  very  sensitive  to  alkali  and  should  not 
be  planted  in  districts  where  much  alkali  is  found. 

Riparia  x  Rupestris  3306. — This  variety  which  is  from  the  same 
cross  is  less  planted  than  3309.  However,  in  California  it  has  usually 
given  as  good  results  as  3309  and  sometimes  better.  It  does  well  in 
fairly  compact  soils,  especially  those  which  are  liable  to  become  very 
moist  for  sometime.  In  years  of  drought,  it  does  better  in  those  places 
than  3309.  It  should  probably  be  given  the  preference  over  3309  in 
the  San  Joaquin  Valley. 

Riparia  x  Rupestris  101-14. — This  hybrid  has  been  little  used  in 
Europe  where  a  pure  Riparia  which  it  resembles  in  adaptation,  is  pre- 
ferred. It  shows  the  influence  of  the  riparia  parent  more  than  the 
others.  It  does  particularly  well  in  rich,  irrigated  soils  and  is  less 
sensitive  to  a  hot  climate  than  the  pure  riparias.  It  is  promising  for 
use  in  suitable  mellow  soil  in  the  central  valleys.  It  has  been  little  used 
in  California  but  deserves  testing,  especially  for  Muscat  and  table 
grapes.  It  is  probably  less  widely  adapted  than  420A  but  it  is  more 
easily  handled  in  the  matter  of  rooting. 

Riparia  x  Berlandieri  420 A. — This  is  the  most  interesting  variety 
of  its  class,  and  is  almost  the  only  one  which  has  been  tried  in  Cali- 
fornia. It  possesses  to  a  marked  degree  the  qualities  of  the  Riparia 
united  with  those  of  the  Berlandieri.  The  Berlandieri  is  resistant  to 
drought  and  grows  well  in  compact  soils,  more  or  less  shallow.  It 
strongly  favors  the  fertility  of  the  scions  it  bears,  and  this  character- 
istic is  always  transmitted  to  its  hybrids.  Unfortunately,  when  pure 
it  does  not  root  well.  The  hybrid  420A  is  adapted  to  rather  compact 
soils  which  may  become  dry  during  the  growing  season.  Its  regularity 
in  production  and  the  quality  of  the  grapes  it  produces  are  very 
notable.  The  percentage  of  successful  bench  grafts  is  low  though  the 
unions  of  those  which  grow  are  excellent.  It  has  the  reputation  in 
France,  common  to  other  Berlandieri  hybrids,  of  developing  slowly  at 
first.  At  Davis  and  Kearney,  however,  it  has  grown  well.  Grafting 
on  rooted  vines  gives  better  results  with  this  stock  than  bench  grafting. 


CiRC.  288]  PHYLLOXERA   RESISTANT   VINEYARDS  7 

Berlandieri  x  Novo  Mexicana  31R. — This  stock  is  more  vigorous 
than  420A,  and  very  fruitful,  but  it  has  not  yet  been  experimented 
with  in  California. 

Rupestris  x  Berlandieri  57R,  99R  and  llOR. — These  three  varieties, 
although  rather  new,  seem  superior  to  all  of  the  old  crosses  of  the  same 
group.  They  promise  to  be  useful  here,  for  they  have  the  vigor  of  the 
Rupestris  combined  with  a  certain  degree  of  the  fruitfulness  of  the 
Berlandieri.  They  are  described  as  promoting  good  bearing  and  as 
resistant  to  drought.  The  latter  characteristic  is  particularly  interest- 
ing under  Californian  conditions.  They  are  adapted  to  shallow  as  well 
as  to  deep  soils,  and  withstand  a  high  percentage  of  lime.  These  char- 
acteristics place  this  group  of  stocks  above  the  group  of  Vinifera  x 
Americans,  and  even  of  that  of  pure  American  stocks.  They  were 
introduced  at  the  University  Farm  vineyards  two  years  ago,  and  are 
being  tested  there. 

Solonis  Hybrids,  1613, 1616. — The  first,  1613,  is  a  hybrid  of  Solonis 
and  Othello  (Solonis  x  Riparia-Labrusca- Vinifera)  ;  the  second  of 
Solonis  and  Riparia.  The  composition  of  the  former  indicates  insuffi- 
cient resistance  to  Phylloxera.  It  has  given  good  results  in  the  vigor 
and  bearing  of  its  scions  but  it  would  be  risky  to  plant  it  except  per- 
haps in  very  rich,  well  irrigated  soils. 

The  second,  1616,  is  five-eighths  Riparia,  two-eighths  Candicans, 
and  one-eighth  Rupestris.  It  is  of  sufficient  resistance  to  Phylloxera 
and  is  adapted  to  good  soils  well  supplied  with  water.  A  valuable 
characteristic  is  its  tolerance  for  alkali  in  which  it  exceeds  most 
resistant  stocks. 

According  to  Mr.  R.  L.  Nougaret  1613  is  very  slightly  infested  by 
nematodes,  and  1616  is  immune.  This  immunity  of  1616  may  be  used 
with  advantage  in  soils  infested  with  that  pest,  for  the  culture  of 
Vinifera  varieties  badly  attacked  by  it. 

Chasselas  x  Berlandieri  41B. — A  well  known  Vinifera  x  American 
hybrid  which  has  withstood  Phylloxera  under  practically  all  condi- 
tions, although  suspected  of  insufficient  resistance  for  a  long  time. 
Old  vineyards  grafted  on  this  stock  are  still  fertile  and  vigorous.  It  is 
considered  only  fairly  vigorous  in  France  and,  like  the  420A,  to  grow 
rather  slowly  for  a  few  years  after  planting.  In  the  experiment  vine- 
yards at  Davis  and  Kearney,  however,  the  vines  grafted  on  this  stock 
have  been  among  the  most  vigorous.  Its  special  value  lies  in  its  great 
power  of  resistance  to  Chlorosis,  although  41B  can  be  grown  in  a 
variety  of  soils,  with  or  almost  without  limestone.  A  disadvantage  of 
this  stock  is  that  it  is  difficult  to  root.  It  gives  a  low  percentage  when 
bench  grafted,  but  it  can  be  easily  field  grafted.     This  variety  is 


8  UNIVERSITY    OF    CALIFORNIA EXPERIMENT    STATION 

adapted  to  fairly  compact  soils  liable  to  become  dry.  The  fruitfulness 
of  its  grafts  is  well  known. 

Suitable  ComMnations  of  Stock  and  Scion. — After  determining  the 
stocks  which  seem  most  suitable  for  the  soil,  climate,  and  other  condi- 
tions of  the  proposed  vineyard,  the  suitability  of  the  scion  variety  to 
the  stock  chosen  should  be  considered.  The  most  important  points  in 
which  combinations  differ  are:  (a)  fruitfulness,  (h)  durability,  (c) 
ease  of  grafting. 

Investigations  at  Davis  and  Kearney  have  given  some  information 
on  these  points  for  some  of  our  most  important  varieties.* 

Yield  and  Quality. — As  already  noted  in  the  preceding  account  of 
promising  resistant  varieties,  certain  stocks  tend  to  promote  fruitful- 
ness of  the  scion  more  than  others.  This  varies,  however,  with  the 
scion  variety.  The  stock  which  promoted  the  highest  average  crop  in 
our  investigations,  420A,  showed  the  most  variation  in  this  respect 
with  different  scions.  Where  the  fruitfulness  of  a  particular  combina- 
tion is  not  known,  it  is  safest  to  use  a  stock  which  shows  a  low  degree  of 
variability  in  this  respect. 

Some  stocks  also  tend  to  promote  quality  in  the  fruit.  This  is 
difficult  to  measure  exactly  but  a  comparison  of  the  sugar  contents  is 
perhaps  the  best  single  standard  of  comparison. 

The  average  standing  regarding  crop  and  sugar  contents  of  the 
varieties  mentioned  tested  at  Davis  and  Kearney  are  as  follows : 

stock —  Sugar  Crop            Crop  x  Sugar 

Berlandieri  x  Eiparia  420A  23.2  245  229 

Chasselas  x  Berlandieri  41B  23.1  213  198 

Eiparia  x  Eupestris  3309  23.6  212  202 

Eiparia  x  Eupestris  3306  24.3  193  189 

Eiparia  X  Eupestris  101-14  22.7  189  173 

Eiparia  gloire  24.7  166  165 

Eupestris  St.  George  24.8  100  100 

.  The  variability  of  each  stock  with  different  scion  varieties  is  shown 
in  fig.  1. 

Durability. — The  length  of  life  of  a  grafted  vine  depends  very 
much  on  the  perfection  of  the  union.  In  the  most  favorable  cases, 
it  is  probably  equal  to  that  of  ungrafted  vines  under  the  same  condi- 
tions. Where  the  suitability  of  stock  and  scion  is  defective,  there  may 
be  imperfect  unions,  and  these  will  result  in  short  lived  vines.  The 
number  of  vines  which  die  during  the  first  five  years  after  planting  is  a 
fair  measure  of  the  durability  of  the  combination.  The  average  per- 
centage of  vines  on  each  stock  dying  yearly  during  the  first  five  years 
with  all  combinations  tried  is  shown  below. 

*  See  Bulletin  331,  Phylloxera-Eesistant  Stocks. 


CIRC.  288] 


PHYLLOXERA   RESISTANT    VINEYARDS 


Stock —  Death  Rate 

Riparia  x  Rupestris  3309  1.9 

Berlandieri  x  Eiparia  420A  2.0 

Chasselas  x  Berlandieri  41B  2.4 

Riparia  x  Rupestris  3306 2.9 

Riparia  gloire  3.2 

St.  George 3.4 


420j\ 

41  B 

3300     II     3306    ||R.  Gloire 

1202 

St.  Geor<§j& 

BL      245 

-             £f3 

1    "  CROP    "     1 

166 

_          160 

100 

k. 

t93 

k 

1               1 

1 

1 

P 

1                    ^J 

^ABIL.ITY 

? 

f 

^■■^^  ^^^^^£ 

^^^mSO 

■ 

-»•«•          .■    -  , 

1 

1 

J5 

J.5 

^ 

30 

u 

SA 

d/ 

Fig.  1. — Record  of  seven  principal  stocks  with  ten  scions. 


The  durability  of  a  graft  depends  as  much  on  the  scion  as  on  the 
stock.  Some  scion  varieties  make  durable  combinations  with  most 
stocks.  Others  are  difficult  to  suit  in  this  respect.  The  tests  at  Davis 
show  the  average  standing  of  some  of  our  principal  varieties  on  all  the 
stocks  tested  as  follows : 

Scion —  Death  Rate 

Sultanina   (Thompson)    0 

Palomino  .7 

Sultana  7 

Petite  Sirah  1.1 

Emperor    1.4 

Malaga    1.7 

Muscat 3.4 

Alicante  Bouschet  6.4 

Tokay    7.1 

Except  the  last  three,  these  are  all  very  good  records.  The  Muscat 
and  Alicante  Bouschet  are  well  known  for  their  instability  when 
grafted.  The  cause  of  the  lack  of  durability  of  the  Tokaj^  at  Davis  may 
have  some  connection  with  its  susceptibility  to  frost  and  black-knot. 


10 


UNIVERSITY    OF    CALIFORNIA EXPERIMENT   STATION 


Ease  of  Grafting. — There  is  considerable  variation  in  the  ease  with 
which  cuttings  of  various  stock  varieties  can  be  made  to  unite  with 
the  scion.  This  is  principally,  however,  a  matter  of  rooting.  If  the 
cutting  does  not  root,  the  graft  dies.  The  Berlandieri  varieties  root 
with  difficulty  and  it  is  usually  necessary  to  root  them  first  before 
grafting. 

For  more  details  on  this  subject  the  reader  is  referred  to  Bulletin 
No.  331,  of  this  Station.  In  the  following  table  are  given  the  three 
combinations  for  some  of  the  principal  varieties  of  raisin,  table  and 
wine  grape,  which  have  been  found  best  at  Davis  and  Kearney  Park, 
most  weight  being  given  to  the  yield  and  durability. 

Resistant  Stock  Recommended 
Scion  Variety —  First  Second  Third 

Muscat  of  Alexandria 41B  420A  3306 

Sultanina  3306  420A  3309 

Black  Corinth  41B  3306  

Sultana 41B  420A  3306 

Tokay  420A  3309                3306 

Malaga  41B               420A             3306 

Emperor  3306  3309                 

Cornichon 3309  3306  '             41B 

Alicante  Bouschet  3306  3309                  420A 

Petite  Sirah  3306  41B               420A 

Valdepenas   3306  3309                  420A 

Gros  Mansenc  41B  420A  3309 

Lagrain 41B  3309  3306 

The  Rupestris  St.  George  is  not  mentioned  at  all  in  this  table.  The 
reason  is  that  it  has  given  generally  the  poorest  results  with  the  seven- 
teen scion  varieties  tested  comparatively  on  various  stocks.  Further- 
more, with  the  exception  of  41B,  none  of  the  Vinifera  x  American 
stocks,  that  in  some  cases  have  given  as  good  results  as  some  pure 
American  or  some  Americo  x  American  hybrids,  have  been  mentioned 
here  for  the  reason  of  their  doubtful  resistance.  All  the  combinations 
listed  have  given  good  results  and  a  choice  among  them  should  be  made 
on  the  basis  of  the  adaptation  of  the  stock  to  the  particular  soil. 

Production  of  Resistant  Cuttings. — In  order  to  establish  a  vine- 
yard on  resistant  roots,  we  must  have  cuttings  of  the  resistant  stock 
from  which  to  produce  the  root  and  cuttings  of  the  desired  vinifera 
variety  for  scions  from  which  to  produce  the  top.  The  scion  cuttings 
are  exactly  the  same  as  those  used  for  ordinary  rootings  of  non- 
resistant  vines  and  are  made  in  the  same  way.  The  resistant  cuttings 
are  made  in  a  similar  way  from  mother  vines  of  the  required  variety 
grown  specially  for  this  purpose. 


CiRC.  288]  PHYLLOXERA   RESISTANT   VINEYARDS  11 

The  number  of  cuttings  obtainable  from  resistant  mother  vines  will 
vary  with  the  variety,  the  soil,  and  the  age  of  the  vines.  Tests  made 
at  Davis  indicate  that  about  25  per  cent  of  the  weight  of  the  wood 
produced  can  be  used  for  No.  1  cuttings  suitable  for  grafting,  and 
about  15  per  cent  for  No.  2  cuttings  suitable  for  rooting.  The  remain- 
ing 60  per  cent  is  waste.  On  the  average  vines,  in  average  soil,  the 
number  of  cuttings  varied  from  50  to  100  No.  1  grafting  cuttings  and 
from  60  to  120  rooting  cuttings. 

PRODUCTION  OF  GRAFTED  RESISTANT  VINES 

There  are  two  general  methods  of  establishing  a  resistant  vineyard. 
One  consists  in  producing  a  grafted  resistant  vine  in  a  nursery  and 
then  planting  this  complete  vine  in  the  vineyard  and  growing  it  in 
practically  the  same  way  as  that  used  for  ungrafted  vines  with  some 
special  precautions  explained  later.  The  other  consists  in  planting 
the  resistant  vine  (cutting  or  preferably  rooting)  directly  in  the  vine- 
yard where  it  is  to  remain  permanently,  grafting  it  later.  The  first  is 
the  better  way  because  it  is  cheaper  in  the  end  and  because  it  gives  a 
more  uniform  vineyard  and  consequently  better  yields. 

Each  of  these  general  methods  has  several  modifications,  the  most 
useful  of  which  are  described  in  this  circular. 

Grafted  Vines  Produced  in  the  Nursery. — There  are  three  methods 
of  producing  nursery  grafted  vines:  (a)  the  scion  cutting  may  be 
grafted  on  the  resistant  cutting  and  then  rooted  in  the  nursery  and 
planted  in  the  vineyard  a  year  later;  (5)  the  resistant  cutting  may  be 
rooted  one  year  in  the  nursery,  dug  up  the  following  spring,  grafted 
and  returned  to  the  nursery  for  a  year  and  planted  out  the  third  year. 
Both  these  methods  are  known  as  '^ Bench  Grafting";  (c)  the  resistant 
cutting  may  be  rooted  for  one  year  in  the  nursery,  grafted  in  place 
without  removal  the  following  spring  and  planted  out  in  the  vineyard 
the  third  spring.    This  is  known  as  ' '  Nursery  Grafting. ' ' 

The  first  method  is  the  most  rapid  and  economical  and  is  usually 
to  be  preferred.  The  second  is  useful  for  varieties  which  root  slowly 
or  with  difficulty  and  for  the  utilization  of  cuttings  of  resistant  stocks 
which  are  too  small  for  grafting  as  cuttings.  The  third  method  avoids 
the  expense  of  digging  and  replanting  the  resistant  rooting  but  pro- 
duces very  large  vines  which  are  expensive  to  dig  and  handle. 

Bench  Grafting. — For  bench  grafting,  cuttings  for  both  stock  and 
scion  should  be  carefully  selected.  They  should  be  true  to  name, 
properly  matured  and  well  supplied  with  starch  reserves.  The  last 
characteristic  is  very  important,  for  neither  union  nor  growth  can  be 
obtained  without  starch.    The  amount  of  this  substance  in  the  tissues 


12 


UNIVERSITY    OF    CALIFORNIA EXPERIMENT   STATION 


is  easily  estimated  by  the  iodine  test,  which  consists  in  covering  a 
slanting  cut  made  on  a  cutting  with  a  few  drops  of  a  solution  contain- 
ing one  gram  of  iodine  in  100  cubic  centimeters  of  alcohol  150  proof,  or 
ordinary  tincture  of  iodine  diluted  with  water.  The  presence  of  starch 
is  shown  by  a  blue  coloration  and  the  darker  the  color  the  better  the 
grafting  wood.  Stock  cuttings  must  be  as  straight  as  possible  (see 
fig.  2).  Their  length  should  vary  with  the  climate  and  the  moisture 
of  the  soil.  For  the  coast  region  a  10-  or  11-inch  cutting  is  best, 
while  for  the  sandy  loam  soils  of  the  interior  valleys,  a  12-  or  14-inch 
stock  is  to  be  preferred. 


rig.  2. — straight  cuttings  suitable  for  grafting.     Variety — Aramon  x 
Eupestris  Ganzin  No.  1. 


Bench  grafting  can  be  begun  as  early  as  January,  and  continued 
until  the  middle  of  April.  Before  grafting,  the  cuttings  should  be 
soaked  in  water  for  twenty-four  hours,  disbudded  thoroughly,  and 
graded  according  to  size.  After  soaking,  the  cuttings  should  be  cut 
to  the  length  required  and  disbudded  with  a  sharp  knife  or  a  small 
pair  of  pruning  shears. 

The  grading  is  best  made  with  the  metal  slot-grader  shown  in  fig.  3. 
The  length  of  the  slot,  which  is  cut  in  a  brass  plate,  is  7  inches,  with 
a  width  of  14  an  inch  at  one  end,  and  14  of  an  inch  at  the  other.  The 
ends  of  the  slot  are  widened  into  circles  I14  i^ich  and  I/2  inch  wide, 
respectively.  The  plate  is  marked  with  guide  lines  which  determine 
the  number  and  size  of  the  grades.  Any  desired  number  of  grades  and 
relation  between  the  grades  can  be  obtained  by  varying  the  position 
of  the  guide  lines.  A  percentage  difference  between  grades  is  the  best 
and  five  or  six  grades  are  sufficient. 


CiRC.  288] 


PHYLLOXERA   RESISTANT    VINEYARDS 


13 


Size 
Size 

Size 
Size 
Size 
Size 


Distance  Between  Lines  for  6,  5,  4  Grade  Sizes 

Five  Sizes  Four  Sizes 

Size  1—1.04  inch  Size  1—1.32  inch 

Size  2 — 1.20  inch  Size  2 — 1.57  inch 
Size  3—1.37  inch 
Size  4—1.58  inch 
Size  5 — 1.81  inch 


Six  Sizes 

1—0.86  inch 

2 — 0.96  inch 

3 — 1.08  inch 

4—1.21  inch 

5—1.36  inch 

6—1.53  inch 


Size  3—1.88  inch 
Size  4—2.23  inch 


F 


Fig.  3. — Slot  grader — side  view  and  front  view. 

Behind  the  slot,  at  three-fourths  of  an  inch,  a  piece  of  iron  as  a  stop 
to  hold  the  cutting,  helps  in  grading  accurately.  With  this  marking 
of  the  grader,  six  size  grades  of  cuttings  are  made,  each  varying  in  the 
same  ratio  from  the  next.  The  cuttings  which  fail  to  enter  the  slot 
or  pass  completely  through  are  discarded  as  too  large  or  too  small  for 
grafting.* 

The  scion  cuttings  are  then  prepared.  They  are  usually  one  bud 
scions,  cut  at  ^^4  of  an  inch  above  each  bud  and  with  1%  to  21/4  inches 
of  internode  below.  They  should  be  soaked  for  about  12  hours,  and 
then  graded,  always  with  the  bud,  either  up  or  down.  At  this  stage,  the 
stocks  and  scion  cuttings  are  ready  to  be  grafted. 

Two  methods  of  grafting  are  used,  according  to  the  type  of  callus- 
ing  adopted.  When  sand  callusing  is  chosen,  the  ordinary  whip  graft 
is  used,  while  in  hot  room  callusing  the  short  or  modified  whip  graft 
is  preferred. 


*  A  fuller  description  of  the  slot  grader  and  method  of  construction  are 
given  in  Bull.  180,  Eesistant  Vines,  pp.  103-105.     (Out  of  print.) 


14 


UNIVERSITY    OF    CALIFORNIA — EXPERIMENT   STATION 


In  the  ordinary  whip  graft,  practiced  by  means  of  a  special  grafting 
knife,  the  upper  end  of  a  cutting  is  cut  at  an  angle  of  a  little  less  than 
30  degrees,  which  gives  a  slanting  cut  about  2%  times  as  long  as  the 
diameter  of  the  cutting.  A  thin  tongue  is  then  made  by  cutting  a 
little  across  the  grain  from  the  first  third  of  the  cut  down  to  the  second 
third,  so  that  the  tongue  extends  the  length  of  the  middle  third  of 
the  cut.  A  similar  cut  and  tongue  are  made  on  the  scion  and  then 
stock  and  scion  are  adjusted  together.  To  facilitate  this  operation, 
the  tongues  are  opened  by  drawing  out  the  knife  obliquely.    The  graft 


A  B 

Fig.  4. — A.  Modified  whip  graft.    B.  Ordinary  whip  graft. 

is  then  tied  with  raffia  or  soft  string  in  a  spiral  with  the  turns  sepa- 
rated one  from  the  other  by  a  small  interval.  This  is  necessary  for  an 
even  callusing  and  the  raffia  must  be  moist  (fig.  4B). 

Other  types  of  grafts  suitable  for  sand  callusing  can  be  made  by 
machines,  but  they  are  inferior  to  skillfully  made  hand  whip  grafts. 

With  rootings  as  stocks,  instead  of  cuttings,  the  various  operations 
described  above  are  the  same  except  that  the  roots  should  be  cut  off 
as  close  as  possible  from  the  original  cutting.  The  grafts  when  made 
are  tied  with  a  No.  16  wire,  in  bundles  of  25,  and  set  at  a  slight  slant 
in  a  sand  pit  with  a  southern  exposure  and  protected  from  rain.  The 
sand  should  be  coarse,  free  from  silt,  and  contain  about  5  per  cent  of 
moisture.  About  2  inches  of  sand  should  cover  the  top  of  the  scions. 
The  grafts  are  ready  for  planting  in  the  nursery  when  they  are  well 
callused. 


CiRC.  288] 


PHYLLOXERA   RESISTANT    VINEYARDS 


15 


For  hot  room  callusin^,  the  short  or 
modified  whip  graft  should  be  used.  To 
make  it,  a  grafting  knife  or  a  whip  grafting 
machine  can  be  used.  The  stocks,  cuttings 
or  rootings,  prepared  and  graded,  are  cut 
with  a  knife  so  as  to  give  a  cut  about  II/2 
times  their  diameter.  The  tongue  is  made 
by  cutting  across  the  grain  and  extending 
from  near  the  top  of  the  cut  to  near  its  bot- 
tom level.  It  should  be  fairly  thin  so  as  to 
avoid  splitting.  The  scion  is  prepared  in 
the  same  manner  and  adjusted  to  the  stock. 
When  the  graft  is  well  made,  it  is  very  solid 
and  does  not  require  tying  (fig.  4A). 

There  are  several  satisfactory  machines 
for  making  the  modified  whip  graft.  The 
one  shown  in  fig.  5  has  been  used  with  suc- 
cess at  the  University  Farm.  It  shapes  a 
stock  or  a  scion  cutting  at  a  single  stroke,  so 
that  a  graft  can  be  made  with  two  strokes. 
A  double  action  machine  of  the  same  type 
makes  a  graft  with  one  stroke. 

The  united  grafts  are  put  into  boxes  for  callusing  in  a  hot  room. 
The  boxes  may  be  of  any  size,  except  for  the  height,  which  is  regulated 
by  the  length  of  grafts.  An  18-inch  height  will  accommodate  grafts 
made  with  10-  or  12-inch  stocks.  A  hinged  side  is  very  convenient 
for  filling  and  emptying  the  boxes.  The  callusing  medium  consists  of 
a  mixture  of  saw^dust  and  coarse  ground  charcoal — three  parts  of  the 
former  to  one  of  the  latter  give  a  good  callusing  mixture.  Further- 
more, the  boxes  must  be  lined  on  all  sides  except  the  top  with  a  2-inch 
layer  of  moss. 

For  filling  them,  a  little  moss  is  put  on  the  bottom  and  sides,  and 
a  single  layer  of  grafts  laid  down  horizontally,  with  the  scions  toward 
the  top  of  the  box  and  at  the  same  level  (fig.  6).  The  butts  rest  on 
the  moss  at  the  bottom  of  the  box.  The  callusing  mixture  is  used  to 
fill  the  space  between  the  grafts,  and  then  another  layer  of  grafts  is 
put  on  the  first,  and  so  on  until  the  box  is  filled.  During  this  process, 
the  layer  of  moss  is  raised  gradually  on  the  sides  and  bottom,  and 
when  the  grafts  are  2  inches  from  the  hinged  side  thej^  are  covered 
with  moss.  The  hinged  side  is  then  closed  and  the  box  put  in  its  normal 
position.  To  insure  good  packing  in  the  box,  necessary  for  good  callus- 
ing, water  is  poured  freely  into  the  box  and  sufficient  callusing  mixture 


Fig.  5. — Grafting  machine 
making  the  modified  ^vllip 
graft. 


16 


UNIVERSITY    OF    CALIFORNIA — EXPERIMENT   STATION 


added  to  just  cover  the  top  of  the  scions.  The  box  is  allowed  to  drain 
and  is  then  covered  with  a  2-inch  layer  of  callusing  mixture,  slightly 
moist.  At  this  stage,  the  box  is  ready  to  enter  the  hot  room.  It  may 
be  kept  in  a  cool  place  if  delay  of  callusing  is  desired. 


wm^msmm 


'iS:«Pfeg 


%^ 


'^^^ 


Fig.  6. — Callusing  box  showing  method  of  filling. 


CiRC.  288] 


PHYLLOXERA   RESISTANT   VINEYARDS 


17 


The  callusing  room  may  be  of  various  forms,  but  must  be  built  so 
as  to  insure  a  uniform  temperature.  The  same  principle  applies  to  the 
heating  system.  A  coal  oil  stove  and  a  two-bulb  electric  stove  have 
been  used  v^ith  success  at  the  University  Farm  in  a  small  room. 

At  a  temperature  of  75°  F.,  callusing  takes  place  within  three 
weeks,  while  at  85°  F.,  the  maximum,  it  is  obtained  within  two  weeks. 
At  the  higher  temperatures  the  callus  formed  is  delicate  and  easily 
injured  by  any  unfavorable  conditions.  No  callusing  takes  place  below 
60°  F.  From  70°  to  75°  F.,  are  the  most  favorable  temperatures. 
During  the  time  the  grafts  spend  in  the  hot  room,  they  must  be  dipped 
occasionally  in  water  of  the  same  temperature  as  that  of  the  room  in 


Fig.  7. — Dipping  vats,  steam  and  water  pipes.     The  white  line  shows  the 
level  of  grafts  in  the  callusing  box. 


order  to  keep  the  butts  continually  moist.  Care  must  be  taken  not  to 
allow  the  water  to  reach  the  level  of  the  unions  because  too  much 
moisture  prevents  the  production  of  callus  (see  fig.  7). 

Two  dippings  are  generally  sufficient  during  callusing.  The  cover 
must  be  kept  rather  dry,  but  may  need  to  be  wetted  slightly  from  time 
to  time.  When  the  callusing  is  complete,  the  grafts  are  gradually 
accustomed  to  the  outside  temperature  by  passing  several  days  in  a 
room  where  the  temperature  is  several  degrees  lower  than  that  of  the 
hot  room.  Then  the  boxes  are  set  under  an  open  shed  and  the  hardened 
grafts  are  ready  for  planting. 

Nursery  Grafting. — This  operation  can  be  done  at  two  different 
seasons  of  the  year.  Cuttings  planted  in  the  spring  in  the  nursery  can 
be  grafted  during  August  and  until  about  September  10,  or  grafted 


18 


UNIVERSITY    OF    CALIFORNIA — EXPERIMENT   STATION 


in  February  or  March.     In  the  first  case,  the  Yema  graft  should  be 
used  exclusively.     This  type  of  graft  is  made  in  three  ways. 

In  the  ordinary  Yema  or  ''bud"  graft,  the  bud  carries  a  certain 
amount  of  wood,  unlike  ordinary  buds.  The  stock  is  cut  as  shown  in 
fig.  8,  II,  by  means  of  a  special  budding  knife,  so  as  to  make  a  groove 
which  will  receive  the  scion.  The  bud  is  removed  from  the  scion  canes 
in  the  same  way  as  the  stock  is  cut  (fig.  8,  I),  except  that  cut  No.  3  is 
made  so  as  to  get  a  plane  surface  below  the  bud.  It  is  then  inserted 
on  the  stock  and  tied  as  shown  in  fig.  8  II. 


Fig.  8. — Yema  grafts.  (1)  How  to  remove  a  bud  from  the  scion  cane.  (2) 
How  to  cut  the  stock,  insert  the  bud  and  tie  the  graft.  (3)  How  the  graft 
should  be  mounded  up.  (4)  Modified  Yema  graft.  (5)  Knife  used  in  Australia 
for  Yema  grafting.     (6)  New  Modified  Yema  graft. 

The  modified  Yema  graft  needs  no  tying,  and  is  more  quickly 
made  than  the  ordinary.  For  preparing  the  stock,  three  cuts  as  a 
minimum  are  necessary,  but  to  remove  the  scion  two  are  sufficient 
(fig.  8,  IV).  These  two  methods  of  Yema  grafting  are  equally 
successful. 

The  third  method  shown  in  figure  8,  VI,  is  the  easiest  of  all  to  make 
by  hand  and  it  has  given  very  good  results.  It  is  essential  that  it 
should  be  tied  below  the  eye  and  especially  above.  Raffia,  small  white 
string,  and  then  strips  of  rubber  are  used  as  tying  materials. 

To  get  good  results,  the  stock  must  be  well  in  sap  at  the  time  of 
grafting,  while  the  buds  must  be  taken  from  parts  of  canes  that  show 
a  ripe  or  dead  leaf  color. 


CiRC.  288]  PHYLLOXERA   RESISTANT   VINEYARDS  19 

The  grafts  must  be  covered  by  mounding  3  inches  of  dirt  above 
the  buds  and  as  soon  as  possible  after  having  been  made  or  they  will 
part.  The  top  of  the  vine  is  not  cut  at  the  time  of  grafting  but  before 
sprouting  in  February  or  March.  The  bud  remains  dormant  until 
the  starting  of  the  sap  in  the  spring. 

One-year-old  resistant  vines  in  the  nursery  can  also  be  grafted  in 
the  spring  ''in  situ."  The  best  methods  of  grafting  are  the  ordinary 
whip  graft  already  described,  and  the  Yema  graft.  Stocks  and  scions 
are  generally  dormant  although  it  does  not  matter  if  the  former  are 
already  sprouting.  In  whip  grafting,  a  scion  with  one  bud  only  should 
be  used.     Unlike  Yema  grafting  in  the  fall,  in  the  spring  the  stock 


Fig.  9. — Yema  grafting  machine. 

must  be  cut  off  immediately  after  grafting,  one-half  an  inch  above 
the  top  of  the  bud.  With  both  methods  all  scion  buds  must  be  covered 
by  a  wide  mound  2  or  3  inches  high  above  the  buds.  The  ordinary 
Yema  graft  can  be  made  by  a  machine  which  works  satisfactorily.  This 
machine  is  particularly  handy  for  cutting  out  the  buds.  It  can  be 
obtained  from  Ulysse  Fabre,  Vaison  (Vaucluse),  France  (fig.  9). 

Numerous  suckers  are  likely  to  be  thrown  out  in  nursery  grafting 
and  it  is  very  important  to  remove  them  as  soon  as  they  appear. 

Planting  and  Care  in  Nursery. — The  planting  of  ungrafted  resist- 
ant stock  cuttings  does  not  differ  from  that  of  common  cuttings.  They 
can  be  planted  by  hand,  in  trenches  opened  with  the  shovel  or  with 
suitable  machinery,  according  to  the  scale  of  the  planting. 

For  bench  grafts,  more  care  is  necessary.  First  of  all,  at  the 
removal  from  the  callusing  boxes,  they  must  be  looked  over  one  by  one. 
All  suckers  from  the  stock  must  be  cut  close,  and  scion  roots  as  well. 
When  the  scion  buds  are  several  inches  long  and  whitish,  it  is  a  good 
practice  to  cut  them  back  to  about  one  inch  in  length.    Trimmed  in  this 


20 


UNIVERSITY    OF    CALIFORNIA EXPERIMENT    STATION 


manner,  the  grafts,  whether  or  not  they  have  roots  at  their  base,  are 
ready  for  planting  in  trenches  dug  to  a  depth  equal  to  the  length  of 
the  grafts.  A  planting  board  as  guide  measuring  approximately  16 
feet  by  4  inches  by  1  inch  marked  with  a  saw  about  every  3  or  4  inches, 
and  easily  held  in  place  by  an  18-inch  cross  piece  at  each  end  by  means 
of  a  spike,  is  indispensable  for  planting  bench  grafts.  Each  graft  is 
placed  opposite  a  notch,  with  the  union  placed  just  above  the  guide  and 
in  contact  with  it.  This  insures  even  spacing  and  a  straight  line 
(fig.  10).     Care  and  regularity  in  these  respects  are  very  important 


Fig.  10. — (a)  Planting  board,     (h)  Diagram  showing  use  of  planting  board 

with  bench  grafts. 


for  success.  When  a  planting  board  has  been  filled,  the  grafts  are 
''kept''  in  their  position  by  dirt  thrown  into  the  trench,  so  that  the 
board  can  be  removed  to  another  portion  of  the  trench.  Water  should 
be  used  at  this  time  to  settle  the  ground  firmly  at  the  base  of  the  grafts. 
The  trench  is  filled  and  a  wide  mound  two  inches  high  above  the 
scions  is  formed  with  loose  soil.  Nothing  will  have  to  be  done  to  the 
grafts  until  July  when  the  shoots  will  measure  several  inches  above  the 
mound.  At  this  time,  it  is  necessary  to  cut  off  scion  roots  and  to  sup- 
press any  suckers  that  have  formed.  For  these  operations,  the  mound 
is  opened  and  then  replaced  as  soon  as  they  are  performed.  An  irriga- 
tion should  follow  this  work  within  a  day  or  two.  Toward  the  end  of 
August,  the  grafts  should  be  gone  over  again  in  the  same  way,  but  this 


CiRC.  288]  PHYLLOXERA   RESISTANT   VINEYARDS  21 

time  the  mound  should  be  lowered  so  as  to  allow  the  unions  to  harden. 
If  mildew  is  feared,  the  grafts  should  be  sulfured.  At  this  time,  the 
nursery  should  be  looked  over  by  a  man  familiar  with  vine  leaves  to 
verify  that  the  grafts  are  not  mixed. 

Digging  and  Selection  of  Stocks. — The  vines  in  the  nursery  can  be 
dug  up  as  soon  as  they  have  lost  their  leaves.  In  a  small  nursery  the 
vines  can  be  taken  out  conveniently  by  using  a  plow  to  remove  as 
much  dirt  as  possible  along  the  rows  of  vines  on  one  side,  and  then  by 
means  of  a  shovel  the  grafts  can  be  removed  without  injury.  In  large 
nurseries,  the  vines  are  dug  up  by  means  of  a  nursery  digger  and 
tractor.  The  digger  cuts  the  roots,  loosens  the  vines,  and  lifts  them  a 
few  inches  so  that  they  can  be  easily  pulled  out  by  hand. 

The  vines  should  now  be  graded.  As  the  top  growth  of  rootings  is 
proportional  to  the  size  of  the  root  system,  their  grading  could  be 
made  safely  from  this  part  of  the  vine.  For  ungrafted  resistant  stocks, 
grade  No.  1  corresponds  to  vines  having  a  minimum  of  four  well  dis- 
tributed and  developed  roots  near  the  base,  and  a  normal  top  growth 
(see  fig.  11a)  ;  grade  No.  2,  to  vines  with  less  than  four  good  roots  or 
with  a  small  top  growth  or  slightly  injured  on  the  trunk;  grade  No.  3, 
or  culls,  is  made  up  of  weak  vines  which  should  be  destroyed. 

Grafts  are  sorted  like  ordinary  rootings  for  top  growth,  and  root 
growth,  but  the  unions  should  also  be  considered.  A  No.  1  graft  should 
have  a  complete,  smooth,  and  solid  union,  a  uniform  root  system  of 
four  to  five  roots,  and  a  corresponding  top  growth  (fig.  115).  Any 
vine  with  one  of  these  parts  defective  is  a  grade  No.  2  vine. 

Growers  should,  whenever  possible,  plant  only  vines  of  No.  1  grade, 
as  experiments  have  shown  that  they  succeed  much  better  than  grade  2, 
and  come  into  bearing  earlier. 


PLANTING  GRAFTED  VINES 

Owing  to  the  nature  of  a  grafted  vine  certain  precautions  relative 
to  planting  operations  are  necessary  to  insure  the  success  of  a  vineyard 
on  resistant  stocks.  First  of  all,  a  thorough  and  deep  preparation  of 
the  soil  is  essential  for  the  proper  development  of  these  vines.  It  is 
well  to  consider  that  the  root  system  of  resistant  stocks  is  weaker 
generally  than  that  of  ungrafted  vines,  and  needs  more  thorough  soil 
preparation.  The  soil  should  be  stirred  to  a  depth  at  least  equal  to 
the  length  of  grafts.  This  work  can  be  done  in  two  ways :  (a)  by  plow- 
ing all  the  ground  to  a  depth  desired,  (&)  by  subsoiling  every  two  or 
three  feet  to  a  depth  of  18-30  inches  according  to  the  type  of  soil 


22 


UNIVERSITY    OF    CALIFORNIA — EXPERIMENT   STATION 


and  its  moisture  content,  and  plowing  10-12  inches  deep.  Grafted 
vines  should  be  *' heeled  in"  carefully  from  the  time  they  are  dug 
from  the  nursery  until  they  are  ready  for  planting  out.  The  union 
should  always  be  covered  in  order  to  prevent  drying  while  the  grafts 
are  heeled  in. 


Fig.  11. — (a)  No.  1  rootings.     (h)  No.  1  bench  grafts. 


CiRC.  288] 


PHYLLOXERA   RESISTANT   VINEYARDS 


23 


At  planting  time,  the  grafts  (fig.  12a)  are  taken  from  the  bundles 
one  by  one,  and  their  base  roots  cut  to  three  or  four  inches  for  planting 
in  holes  (fig.  126),  or  to  one-fourth  of  an  inch  for  planting  with  a 
dibble.  Other  roots  appearing  at  nodes  or  on  the  scion  should  be  cut 
very  close.  All  the  growth  made  by  the  scion  except  the  best  cane  is 
removed  and  this  cut  to  a  stub  with  two  buds.  After  this  preparation, 
the  grafts  are  placed  in  a  5-gallon  oil  can  with  a  few  inches  of  water, 
and  taken  out  one  by  one  as  they  are  planted. 


Fig.  12. — (a)  Bench  graft  before  trimming,     (b)  Bench  graft  ready 
for  planting,     (c)  Bench  graft  planted. 


In  planting  in  a  hole,  the  roots  should  always  rest  on  good  mellow 
soil,  and  the  union  should  be  placed  at  one  and  a  half  inches  above  the 
level  of  the  ground.  This  is  to  prevent  the  scion  from  sending  out 
roots  which  would  destroy  the  value  of  the  grafted  vine.  Loose  dirt  is 
thrown  on  the  roots  till  the  hole  is  one-third  filled  and  then  firmed  with 
the  foot.  The  hole  is  almost  filled  up,  stamped  a  second  time,  and  a 
wide  mound  of  loose  dirt  about  two  inches  above  the  top  of  the  graft 
is  made  (fig.  12c).  This  mound  must  not  be  disturbed  until  the 
shoots  have  come  out  and  are  six  or  eight  inches  long. 


24 


UNIVERSITY    OF    CALIFORNIA — EXPERIMENT   STATION 


When  grafts  are  planted  with  a  dibble,  the  soil  should  be  firmed 
around  the  base,  and  a  mound  built  around  the  vine  as  above.  With 
good  grafts  in  good  condition  and  the  work  properly  done  as  explained, 
as  good  a  stand  is  obtained  as  with  ungraf  ted  vines. 


FIELD   GRAFTING 


When  ungrafted  resistant  vines  have  been  planted  in  the  vineyard 
they  should  be  grafted  as  soon  as  they  are  sufficiently  large.  This 
condition  is  generally  reached  in  one  year, 
but  some  growers  prefer  to  graft  when  the 
stocks  are  two  years  old.  The  ordinary 
whip-graft  method  is  used  almost  exclu- 
sively. In  this  case,  a  scion  with  two  buds 
is  used  instead  of  one,  as  in  bench  grafting 
and  nursery  grafting.  When  stock  and 
scion  are  of  the  same  size,  a  perfectly 
smooth  graft  can  be  made  (fig.  13A).  If 
the  stock  is  larger  than  the  scion,  the  stock 
should  be  whip-grafted  on  the  side  (fig.  13, 
B  and  C).  The  grafts  should  be  tied  with 
raffia  soaked  in  water.  Whip  grafting  in 
the  field  should  be  done  from  February  1 
to  April  15  according  to  the  region,  and  the 
soil,  which  should  be  in  good  friable  condi- 
tion and  not  too  wet. 

The  Yema  graft  can  also  be  used.  The 
Yema  graft  in  the  fall  is  especially  suitable 
for  field  grafting.  If  a  few  vines  do  not 
take,  it  is  possible  to  regraft  them  in  the 
spring  according  to  the  ordinary  whip- 
graft  method.  By  the  combined  use  of  a..  Whip  ^aft  wHh  stofrand 
these  two  grafts  a  very  good  stand  can  be  scion  of  equal  diameter.  B 
,  ,    .       T  .  and  C.  Whip  graft  of  a  stock 

obtained  m  one  year.  larger  than  the  scion. 


15?n-5,'25 


